User-wearable devices, such as activity monitors or actigraphs, have become popular as a tool for promoting exercise and a healthy lifestyle. Such user-wearable devices can be used, for example, to measure heart rate, steps taken while walking or running and/or estimate an amount of calories burned. Additionally, or alternatively, a user-wearable device can be used to monitor sleep related metrics. User-wearable devices, such as smart watches, can additionally or alternatively be used to provide alerts to a user. Such user-wearable devices are typically battery operated. Because such user-wearable devices are often used to perform numerous functions that consume power, if not appropriately designed and operated the battery life of such devices can be relatively short, which is undesirable.